Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 595

April 26, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2011, 4:34 PM EDT for 4 states. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Apr 26, 2011, 4:34 PM EDT (20:34 UTC)
Expired: Apr 26, 2011, 5:30 PM EDT
In force: 56 min
Issued by: the Storm Prediction Center

All 82 counties

Allegany County, MD, Garrett County, MD, Washington County, MD, Caswell County, NC, Guilford County, NC, Person County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, Charlotte County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Danville, VA, City of Galax, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Culpeper County, VA, Fauquier County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Frederick County, VA, Greene County, VA, Halifax County, VA, Henry County, VA, Highland County, VA, Madison County, VA, Montgomery County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Patrick County, VA, Pittsylvania County, VA, Prince Edward County, VA, Rappahannock County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, Barbour County, WV, Berkeley County, WV, Braxton County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Harrison County, WV, Jefferson County, WV, Lewis County, WV, Marion County, WV, Mineral County, WV, Morgan County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Taylor County, WV, Tucker County, WV, Upshur County, WV, Webster County, WV

The radar

The Roanoke radar (KFCX), 102 km from the middle of the area, began a volume at 20:38 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 8.6 hours before the alert went out and 63 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 106 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 720 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 211 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 26, 1:18 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett, Washington	57 min
Apr 26, 1:49 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	56 min
Apr 26, 1:49 PM EDT	Severe Thunderstorm Watch	SPC	Garrett	7 hr
Apr 26, 2:09 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Washington	7 hr
Apr 26, 7:44 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett, Washington	61 min
Apr 26, 2:16 PM EDT	Mesoscale Discussion	SPC	Anson, Beaufort, Bertie, Bladen, Camden, Chatham and 43 more	59 min

Nearby

Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in West Virginia, 2011 Mesoscale Discussions in North Carolina, 2011 Every mesoscale discussion in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.